/*
 * The contents of this file are subject to the Mozilla Public
 * License Version 1.1 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * The Original Code is MPEG4IP.
 *
 * The Initial Developer of the Original Code is Cisco Systems Inc.
 * Portions created by Cisco Systems Inc. are
 * Copyright (C) Cisco Systems Inc. 2001.  All Rights Reserved.
 *
 * Contributor(s):
 *      Dave Mackie     dmackie@cisco.com
 */

#include "src/impl.h"

namespace mp4v2
{
    namespace impl
    {

        ///////////////////////////////////////////////////////////////////////////////

        MP4HdlrAtom::MP4HdlrAtom(MP4File &file)
            : MP4Atom(file, "hdlr")
        {
            AddVersionAndFlags(); /* 0, 1 */
            AddReserved(*this, "reserved1", 4); /* 2 */
            MP4StringProperty *pProp = new MP4StringProperty(*this, "handlerType");
            pProp->SetFixedLength(4);
            AddProperty(pProp); /* 3 */
            AddReserved(*this, "reserved2", 12); /* 4 */
            AddProperty( /* 5 */
                new MP4StringProperty(*this, "name"));
        }

        // There is a spec incompatiblity between QT and MP4
        // QT says name field is a counted string
        // MP4 says name field is a null terminated string
        // Here we attempt to make all things work
        void MP4HdlrAtom::Read()
        {
            // read all the properties but the "name" field
            ReadProperties(0, 5);

            uint64_t pos = m_File.GetPosition();
            uint64_t end = GetEnd();
            if (pos == end)
            {
                // A hdlr atom with missing "name".
                // Apparently that's what some of the iTunes m4p files have.
                return;
            }

            // take a peek at the next byte
            uint8_t strLength;
            m_File.PeekBytes(&strLength, 1);
            // if the value matches the remaining atom length
            if (pos + strLength + 1 == end)
            {
                // read a counted string
                MP4StringProperty *pNameProp =
                    (MP4StringProperty *)m_pProperties[5];
                pNameProp->SetCountedFormat(true);
                ReadProperties(5);
                pNameProp->SetCountedFormat(false);
            }
            else
            {
                // read a null terminated string
                try
                {
                    // Unfortunately, there are some invalid mp4 writers that don't
                    // null the hdlr name string.  Generally this will be "automatically"
                    // terminated for them by the size field of the subsequent atom.  So if
                    // our size is off by one...let it slide.  otherwise, rethrow.
                    // The Skip() call will set our start to the correct location
                    // for the next Atom. See issue #52
                    ReadProperties(5);
                }
                catch(Exception *x)
                {
                    if( m_File.GetPosition() - GetEnd() == 1 )
                        delete x;
                    else
                        throw x;
                }
            }

            Skip(); // to end of atom
        }

        ///////////////////////////////////////////////////////////////////////////////

    }
} // namespace mp4v2::impl
